The present invention relates, in general, to heat sink assemblies for electrical components and, more specifically, to heat sinks that employ a resilient biasing element to establish thermal contact between the heat generating electronic components mounted on the surface of a circuit board and the heat sink.
Electric components generate heat that cannot be adequately dissipated in ambient conditions. The heat that is generated from an electrical component must be transferred away from the electrical component. If the heat is not removed, the performance of the electrical component will deteriorate. An effective way to remove heat from electrical components is to securely position the electrical component in thermal contact with a heat sink. A heat sink assembly generally contains a housing that is formed from a material, such as aluminum, that readily conducts heat; such construction makes the housing capable of performing the duties of a heat sink. The housing has the ability to draw the heat from the electrical component and to spread the heat over a large surface area that is exposed to the environment. Typically the housing is lined with a film that is electrically insulative, so the function of the electrical components is not affected.
Surface mounted electrical components have been employed in other heat sink assemblies, such as U.S. Pat. No. 5,280,409 issued Jan. 18, 1994 to Sun Microsystems ad U.S. Pat. No. 5,307,236 issued Apr. 26, 1994 to Alcatel Telspace, however these inventions do not allow for variation in configuration of the surface mounted electrical components, a slight change in the electrical component would require a substantial redesign of the whole assembly.
Resilient biasing elements have been utilized to retain electrical components in thermal contact with the housing. U.S. Pat. No. 4,845,590 issued Jul. 4, 1989 and U.S. Pat. No. 5,274,193 issued Dec. 28, 1993, both assigned to the assignee of the present invention have demonstrated a satisfactory apparatus utilizing a resilient biasing element; however, these inventions can only accommodate electrical components that are attached perpendicularly to a circuit board.
The essential components of these heat sink assemblies are those components that provide or force thermal contact between the electrical components and the housing. It is desirable to increase the level of robustness and decrease the complexity of these essential components when compared to the prior art. It is also desirable, for both reliability and packaging considerations, to use electrical components that are mounted on the surface of a circuit board.
According, it is an object of this invention to provide an improved system for ensuring a thermal contact between a surface mounted electrical component and a housing. The present invention uses a resilient biasing element to ensure that the electrical components mounted on the surface of a circuit board are in thermal contact with the housing. The resilient biasing element is comprised of a body member with a plurality of protruding resilient fingers. The present invention also provides various means to establish thermal contact between the electrical components and the heat sink housing. This thermal contact can be established through a thermal via incorporated in the circuit board, through the resilient biasing element, or by direct contact between the electrical component and the housing.
It is another object of the current invention to design a heat sink assembly that can be easily manufactured and be adaptive to various circuit board configurations. The present invention's use of a resilient biasing element comprised of a body member with a plurality of protruding resilient fingers help to minimize the number of screws or other attachment devices that are needed, as well as, eliminate the need for precise placement of the circuit board and of the electrical components on the surface of the circuit board. The present invention also allows for dissimilar electrical components to be attached to the circuit board, i.e. non-surface mounted electrical components.
It is yet another object of the present invention to design a heat sink assembly that requires a minimal amount of space. The present invention employs a parallel arrangement of housing, circuit board with plurality of electrical components, and resilient biasing element which helps to minimize the overall height of the entire heat sink assembly.
Additional benefits and advantages of the present invention relates from a reading of the subsequent description of the preferred embodiment and the appended claims, taken in conjunction with the accompanying drawings.